1. Technical Field
The present disclosure is directed to an electrochrome element driver and to an integrated circuit module for an electrochrome driver.
2. Description of the Related Art
Electrochromism is a phenomenon found in various chemical substances. These chemical substances, such as polyaniline or tungsten oxide, have the property of reversibly changing color when electrical power is supplied to them. Common electrochrome elements, also referred to as electrochromatic elements, are glass elements, whose levels of transparency change depending on the drive signals applied to them. In the automotive industry, electrochrome elements are for example used for tintable glass roofs or for rear view mirrors. In the case of a rear view mirror, the change in the transparency level of the mirror glass results in a change of the brightness of the reflection seen by the driver. As there are various situations, wherein the driver is blinded by the reflection in the rear view mirror, such as a following car inadvertently having the high beams switched on or the rising sun shining on the back side of the car, electrochrome element mirrors are an important safety feature.
As modern electrochrome element mirrors use substantial amounts of electrical power, they are commonly supplied by the car/truck battery in automotive applications. In order to drive the electrochrome element with appropriate voltages and currents, a previously used approach was a resistor divider circuit. In this approach, the car battery is connected to a first terminal of a resistor and the electrochrome element is connected between the second terminal of the resistor and ground. Accordingly, the voltage and current supplied to the electrochrome element are reduced as compared to a direct connection of the electrochrome element to the car battery, with the level of reduction being determined by the resistor value. However, a large variation of transparency level changing times has been observed over various operation scenarios. Moreover, it has been observed that the life expectancy of electrochrome elements in the automotive industry has been poor when compared to other applications, with a failure of the electrochrome element potentially being a safety hazard to the driver.
Accordingly, it would be beneficial to provide an electrochrome element driver that allows for an increased life expectancy of the driven electrochrome element.